1. Field of the Invention
This invention relates to a manufacturing method for a membrane member which may be used for an electron beam transmission window of an electron beam irradiation tube, a stencil mask for electron beam exposure, a mask for X-ray exposure and so on.
2. Background Art
For the stencil mask for electron beam exposure, the mask for X-ray exposure, etc., a membrane member having a film thickness of about several micrometers (μm) is used. Japanese Unexamined is Patent Publication (kokai) No. 5-165198 discloses a technique to form such a membrane member on a silicon substrate by means of a semiconductor processing technique, such as exposure and etching.
The membrane member of this kind is also applicable to a variety of applications besides the above-mentioned mask, for example, an electron beam transmission window of an electron beam irradiation tube. As application demands, it may be required to thin a thickness of the membrane member to the submicron degree.
When a membrane member gets thinner in this way, the strength of the membrane member itself is also weakened, so that it may be broken with ease. Therefore, for a membrane member used for the electron beam transmission window of the electron beam irradiation tube, there is an attempt to provide a support beam on one side of the membrane member in order to assure a sufficient strength required for the membrane member. However, it seems that this attempt is still insufficient. Additionally, if this kind of membrane member gets thin and is further applied to an application under the influence of heat, the membrane member may be deformed due to heat.